John Cadogan is a popular Australian "automotive expert". He recently put up a video about rust observed on BYD Atto 3s:
His conclusion is that there's not necessarily a real issue to be concerned about here, though he recommends that BYD, as a nascent brand seeking to establish a good reputation in Australia, publicly address the details of galvanic protection on the Atto 3 to reassure current and potential customers.
More interesting is the claim he sources in the video that
most vehicles produced in China for the domestic market are not galvanized. Is this accurate?
P.S. I saw my first BYD Atto 3s on the streets of Adelaide today. Two of them, about 30 minutes apart.